"Some of the country's largest electric utilities were among the most enthusiastic supporters last month when Sens. John Kerry (D-Mass.) and Joe Lieberman (I-Conn.) rolled out their climate and energy bill. ...

But several weeks later, utility industry officials have largely stayed clear of the spotlight on lobbying for the plan that would place mandatory limits on their greenhouse gas emissions, which contribute about a third of the nation's annual total.

Their silence worries environmentalists and others who face a shrinking window to pass legislation this year and are throwing millions of dollars into their own last-ditch ad campaigns aimed at swaying swing-vote senators."